Demeclocycline — Compare Prices at US & Canada Pharmacies

Demeclocycline is an older tetracycline-class antibiotic, once used for a range of bacterial infections including Rocky Mountain spotted fever, various rickettsial diseases, and certain sexually transmitted infections — uses it shares with other tetracyclines like doxycycline, which has largely replaced it for these indications because it's better tolerated and dosed less frequently.

Demeclocycline has a distinctive second life today: because of a side effect that would be unwanted for most drugs — it interferes with the kidney's ability to concentrate urine — clinicians sometimes use it off-label to treat SIADH (syndrome of inappropriate antidiuretic hormone secretion), a condition that causes dangerously low blood sodium. By deliberately inducing a mild, reversible form of diabetes insipidus, demeclocycline helps the kidneys excrete more free water, correcting the sodium imbalance. This use isn't on the FDA label but is well established in clinical practice, particularly when other SIADH treatments aren't tolerated or available.

Like all tetracyclines, demeclocycline carries the class-wide warnings: it shouldn't be used during the second half of pregnancy or in children up to age 8 because of the risk of permanent tooth discoloration, and it increases sensitivity to sunlight — demeclocycline in particular has a reputation for causing a more pronounced photosensitivity reaction than some other tetracyclines, so sun protection is especially important while taking it.

Contraindications

CONTRAINDICATIONS This drug is contraindicated in persons who have shown hypersensitivity to any of the tetracyclines or any of the components of the product formulation.

Warnings

WARNINGS DEMECLOCYCLINE HCl, LIKE OTHER TETRACYCLINE-CLASS ANTIBIOTICS, CAN CAUSE FETAL HARM WHEN ADMINISTERED TO A PREGNANT WOMAN. IF ANY TETRACYCLINE IS USED DURING PREGNANCY, OR IF THE PATIENT BECOMES PREGNANT WHILE TAKING THESE DRUGS, THE PATIENT SHOULD BE APPRISED OF THE POTENTIAL HAZARD TO THE FETUS. THE USE OF DRUGS OF THE TETRACYCLINE CLASS DURING TOOTH DEVELOPMENT (LAST HALF OF PREGNANCY INFANCY AND CHILDHOOD TO THE AGE OF 8 YEARS) MAY CAUSE PERMANENT DISCOLORATION OF THE TEETH (YELLOW-GRAY-BROWN). This adverse reaction is more common during long-term use of the drugs but has been observed following repeated short-term courses. Enamel hypoplasia has also been reported.